The outer planets and their cannibalistic past?

The planets Uranus and Neptune inhabit the furthest out bit of the solar system before the Kuiper belt. They are by far the least studied of the gas giants and what we have seen of them indicates something a little unusual. Over on Discovery, Ray Villard looks at recently emerging evidence that early on in the lifetime of the solar system, these minigiants roamed about swallowing large Earth like planets. The implications aren’t just relevant to why the spin axis of Uranus is so strange, or the magnetic structures so weird, but also understanding planetary migration and evolution in our own solar system is important for understanding that in planetary systems around other stars.